DC/DC converter circuits are widely used in battery-powered portable devices. Examples of such devices include: a smart phone, a smart watch, a camera, a media player and a number of other portable digital devices. In order to extend battery life, those skilled in the art recognize a need for high efficiency operation under a wide load range. In many instances, the total efficiency of the device is limited by the efficiency of the included inverting buck-boost converter. The reason for this is because greater switching losses arise in the inverting buck-boost converter and a more complex driving circuit design is needed for the inverting buck-boost converter. There is accordingly a need in the art to maximize the battery life by improving the efficiency of the inverting buck-boost converter.